A typical jaw crusher includes a stationary jaw and a moveable jaw spaced to define a crushing chamber in between. The jaws each include a face having a series of generally vertical corrugations. Aggregate material is fed into the crushing chamber and is crushed by the intermeshing corrugations as the moveable jaw is moved repeatedly toward and away from the stationary jaw.
The jaws experience tremendous forces during operation of the crusher, and it is thus important that the stationary jaw be firmly secured to the crusher frame during operation. For example, due to the angle between the moveable jaw and the stationary jaw, the moveable jaw applies a cyclic upward load against the stationary jaw. Accordingly, the stationary jaw must be firmly secured against vertical movement. Moreover, due to the aggregate being wedged between the opposing corrugations, the repeated cyclic load applied against the stationary jaw also tends to shift the stationary jaw horizontally (i.e., from side to side within the crusher frame in a direction generally perpendicular to the frame sidewalls). Any undesired movement of the stationary jaw, whether vertical or side-to-side, leads to excess wear and tear on the stationary jaw and the crusher frame, increased down time, and hence increased operational cost of the crusher. It is thus important that the stationary jaw be firmly secured against any up and down and side-to-side movement.
On a typical jaw crusher, and as shown in FIG. 4, the stationary jaw 112 is secured to a portion of the frame 120 against side-to-side movement using wedge shaped key plates 132 which bear against vertical lugs 154, 158 on each side of the stationary jaw 112. After the stationary jaw 112 is positioned on the crusher frame 120, the key plates 132 are driven downwardly and secured to the crusher sidewalls 122, 124, such that the stationary jaw 112 is secured by friction between the stationary jaw side lugs 154, 158 and the corresponding edges 155, 157 on the adjacent key plates. The key plates are then bolted to the crusher sidewalls.
Unfortunately, the high side-to-side forces applied to the stationary jaw during operation of the crusher may sometimes overcome the frictional connection between the key plates and the lugs on the side of the stationary jaw, resulting in side-to-side movement of the stationary jaw. In the event the force on the frictional connection is increased, the side-to-side forces may be sufficient to break the connecting bolts used to secure the key plates to the crusher sidewalls. If so, any movement of the stationary jaw both reduces crushing forces and also damages the crusher frame due to the peening effect caused by the jaw repeatedly pounding against the frame.
Accordingly, an improved system for securing the stationary jaw against side-to-side movement is desired.